[Chromecast] Use ScopedTemp[File|Dir] in tests.

chromecast/app/BUILD.gn

 # Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//testing/test.gni")
 import("//tools/grit/grit_rule.gni")
 
 source_set("app") {
   sources = [
     "cast_main_delegate.cc",
@@ skipping 37 matching lines @@
 test("cast_shell_unittests") {
   sources = [
     "linux/cast_crash_reporter_client_unittest.cc",
   ]
 
   deps = [
     ":cast_crash_client",
     "//base",
     "//base/test:run_all_unittests",
     "//base/test:test_support",
+    "//chromecast/base:test_support",
     "//chromecast/crash",
     "//chromecast/crash:test_support",
     "//testing/gtest",
   ]
 }
 
 grit("resources") {
   source = "//chromecast/app/resources/shell_resources.grd"
 
   resource_ids = "//chromecast/app/resources/resource_ids"
@@ skipping 61 matching lines @@
     "chromecast_settings_ta.pak",
     "chromecast_settings_te.pak",
     "chromecast_settings_th.pak",
     "chromecast_settings_tr.pak",
     "chromecast_settings_uk.pak",
     "chromecast_settings_vi.pak",
     "chromecast_settings_zh-CN.pak",
     "chromecast_settings_zh-TW.pak",
   ]
 }